Petroleum energy source is being depleted. A refuse plastic fuel (RPF) was proposed as an alternative energy source that can replace the petroleum energy source. According the guideline number 2003-127 issued by the Korean Mistry of Environment, RPF is a solid fuel that is produced by the steps of selecting, shredding, dehydrating, and forming a flammable waste plastic and contains a waste plastic in the amount of 60% or more of the solid fuel. The calorific value of waste plastic solid fuel (or PRF) is about 6,000˜8,700 kcal/kg), which is similar to that of bituminous coal. The waste plastic solid fuel is cheap as it is produced from a waste plastic. It provides economic benefit by recycling a waste plastic. Combustion gas generated when a waste plastic is incinerated in an incinerator does not cause corrosion of parts of the incinerator. No special facility is required to be provided at a storage tank of a waste plastic. In addition, waste plastic solid fuel is used as an alternative energy source in many places.
Various structures of waste plastic solid fuel incinerators have been proposed, for example, as disclosed in Korean Patent No. 10-814447 (“Industrial Boiler Using Refused Plastic Fuel”) and Korean Patent No. 10-1342392 (“Structure for Combustion of Solid Fuel and Incinerator Having Same Structure”).